Finite volume and response surface methodology based performance prediction and optimization of a hybrid earth to air tunnel heat exchanger

• Steady state 2-D analysis of earth to air tunnel heat exchanger using FEM approach.
• Steady state 2-D analysis of conventional solar air heater using FEM approach.
• Analysis of earth air tunnel heat exchanger using RSM approach.
• Analysis of variance and process optimization.

In the present investigation, finite volume method is applied for the thermal performance prediction of a hybrid earth to air tunnel heat exchanger whereas process parameters are optimized using response surface methodology. A commercial CFD based software-ANSYS Fluent is used to simulate the heat exchanger. RNG k–ɛ turbulence model was selected to carry out a two-dimensional simulation modelling. Moreover, response surface methodology is applied to analyse the results of finite volume method and to optimize the process parameters of hybrid earth to air tunnel heat exchanger (HEAHX). The numerical results obtained from HEAHX are compared with that of individual EAHX. It is found that performance of HEAHX is about three times higher than as compared to individual EAHX. In addition, the theoretical results of present study are validated with theoretical results obtained from previous works and a good agreement is achieved. The maximum difference between the outlet and inlet air temperatures of hybrid and individual earth to air heat exchangers at the optimum value of input parameters are found to be 49.83 K and 14.4 K, respectively.